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LT6016/LT6017

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APPLICATIONS INFORMATION

Supply Voltage

The positive supply pin of the LT6016/LT6017 should

be bypassed with a small capacitor (typically 0.1μF) as

close to the supply pins as possible. When driving heavy

loads an additional 4.7μF electrolytic capacitor should be

added. When using split supplies, the same is true for

the V– supply pin.

The LT6017 consists of two dual amplifier dice assembled

in a single DFN package which share a common substrate

(V–). While the V– pins of the quad (pins 5 and 7) must

always be tied together and to the exposed pad underneath,

the V+ power supply pins (pins 16 and 18) may be sup-

plied independently. The B and C channel amplifiers are

supplied through V+ by pin 16, and the A and D channel

amplifiers are supplied by pin 18. If pin 16 and pin 18 are

not tied together and are biased independently, each V+ pin

should have their own dedicated supply bypass to ground.

Shutdown

While there are no dedicated shutdown pins for the LT6016/

LT6017, the amplifiers can effectively be shut down into

a low power state by removing V+. In this condition the

input bias current is typically less than 1nA with the inputs

biased between V– and 76V above V–, and if the inputs are

taken below V–, they appear as a diode in series with 1k of

resistance. The output may be pulled up to 50V above the

V+ power supply in this condition (See Figure 1). Pulling

the output pin below V– will produce unlimited current

and can damage the part.

Reverse Battery

The LT6016/LT6017 are protected against reverse battery

voltages up to 50V. In the event a reverse battery condi-

tion occurs, the supply current is typically less than 5μA

(assuming the inputs are biased within a diode drop from

V–). For typical single supply applications with ground re-

ferred loads and feedback networks, no other precautions

are required. If the reverse battery condition results in a

negative voltage at the input pins, the current into the pin

should be limited by an external resistor to less than 10mA.

Inputs

Referring to the Simplified Schematic, the LT6016/LT6017

has two input stages: a common emitter differential input

stage consisting of PNP transistors Q1 and Q2 which

operate when the inputs are biased between V– and 1.5V

below V+, and a common base input stage consisting of

PNP transistors Q3 to Q6 which operate when the common

mode input is biased greater than V+ –1.5V. This results

in two distinct operating regions as shown in Figure 2.

For common mode input voltages approximately 1.5V or

more below the V+ supply (Q1 and Q2 active), the com-

mon emitter PNP input stage is active and the input bias

current is typically under ±2nA. When the common mode

input is within approximately 1V of the V+ supply or higher

Figure 1. LT6016/LT6017 Fault Tolerant Conditions

INPUTS DRIVEN ABOVE

SUPPLY TOLERANT

–

OK!

80V

REVERSE BATTERY

TOLERANT

–50V

–

OK!

INPUTS DRIVEN BELOW

GROUND TOLERANT

25V

TRANSIENT

–

OK!

LARGE DIFFERENTIAL

INPUT VOLTAGE

TOLERANT

–

OK!

80V

OUTPUT DRIVEN ABOVE THE

V+ SUPPLY (IN SHUTDOWN)

TOLERANT

–

OK!

60167 F01

50V

–

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